To improve the starting behavior and the comfort when outside temperatures are cold, many internal combustion engines—at least optionally—have a heating device, by means of which the coolant of the internal combustion engine can be preheated. Such heating devices are also offered for retrofitting and can be operated by connecting them to an external power source. Modern internal combustion engines also mostly have a control device by means of which all sequences and control elements of the internal combustion engine can be controlled to take account of the wishes of the driver, driving comfort, safety functions and emission behavior etc. To this end the control device exerts influence on manipulated variables influencing the torque of the internal combustion engine, such as the amount of fuel to be injected for example, the ignition angle, the amount of fresh air supplied or the exhaust gas feedback rate. This is intended to optimize the engine combustion and the torque delivered.
The starting of the internal combustion engine is also controlled by the control device. To guarantee secure cold starting of the internal combustion engine even when outside temperatures are low, it is known that the amount of fuel needed for starting can be determined as a function of the coolant temperature of the internal combustion engine.
With an internal combustion engine which is equipped with a heating device as described above for heating the coolant, the starting behavior of the internal combustion engine can be noticeably adversely affected however. As well as the greater inconvenience of the long start time, increased pollutant emissions can also result.